/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.drill.exec.planner.sql.parser;

import org.apache.calcite.sql.SqlCall;
import org.apache.calcite.sql.SqlDescribeTable;
import org.apache.calcite.sql.SqlIdentifier;
import org.apache.calcite.sql.SqlKind;
import org.apache.calcite.sql.SqlLiteral;
import org.apache.calcite.sql.SqlNode;
import org.apache.calcite.sql.SqlOperator;
import org.apache.calcite.sql.SqlSpecialOperator;
import org.apache.calcite.sql.SqlWriter;
import org.apache.calcite.sql.parser.SqlParserPos;
import org.apache.calcite.util.ImmutableNullableList;

import java.util.List;

/**
 * Sql parser tree node to represent statement:
 * { DESCRIBE | DESC } tblname [col_name | wildcard ]
 */
public class DrillSqlDescribeTable extends SqlDescribeTable {

  private final SqlNode columnQualifier;

  public static final SqlSpecialOperator OPERATOR =
    new SqlSpecialOperator("DESCRIBE_TABLE", SqlKind.DESCRIBE_TABLE) {
    @Override
    public SqlCall createCall(SqlLiteral functionQualifier, SqlParserPos pos, SqlNode... operands) {
      return new DrillSqlDescribeTable(pos, (SqlIdentifier) operands[0], (SqlIdentifier) operands[1], operands[2]);
    }
  };

  public DrillSqlDescribeTable(SqlParserPos pos, SqlIdentifier table, SqlIdentifier column, SqlNode columnQualifier) {
    super(pos, table, column);
    this.columnQualifier = columnQualifier;
  }

  @Override
  public List<SqlNode> getOperandList() {
    return ImmutableNullableList.<SqlNode>of(getTable(), getColumn(), columnQualifier);
  }

  @Override
  public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
    super.unparse(writer, leftPrec, rightPrec);
    if (columnQualifier != null) {
      columnQualifier.unparse(writer, leftPrec, rightPrec);
    }
  }

  public SqlNode getColumnQualifier() { return columnQualifier; }

  @Override public SqlOperator getOperator() {
    return OPERATOR;
  }

}
